This invention relates to a method of manufacturing building or construction related components such as floor tiles, ceiling tiles, trim moldings, corner guards, sound proofing or insulating panels, truck and boat dock bumpers and the like.
It is known to form door panels, and other construction type panels, as well as decorative wall tiles, in a sandwich type configuration wherein an outer shell is combined with a core comprising a foamed plastic material. For example, in U.S. Pat. No. 3,811,996, a composite, artificial wall tile is disclosed wherein an upper sheet, provided with a decorative appearance, is combined with a second, rigid backing sheet. These sheets are positioned on either side of a layer of resilient material, such as polyurethane foam, and secured about their respective free edges by heat sealing, epoxy adhesive, or the like.
In U.S. Pat. No. 3,844,523, there is disclosed a method of molding foamable materials to form furniture products, picture frames, trim, simulated ceiling beams and the like, wherein a mold is initially sprayed over its entire interior surface with a release agent and/or a barrier coat before a foam material is poured into the mold. The release agent enables the foam molded part to be easily removed from the mold while, a barrier coat if utilized, adheres to the foam and becomes a continuous outer surface of the foam part.
In U.S. Pat. No. 4,221,624, there is disclosed a method of manufacturing sheet material comprising a foamed core and upper and lower thermoplastic skins, all three of which are coextruded.
U.S. Pat. No. 4,463,043 discloses building panels wherein one or more outer layers of cured resin are sandwiched about foam core blocks, with or without stiffening webs between the blocks.
In U.S. Pat. No. 3,844,523, a structural door panel frame is covered with relatively thin surface skins of acrylanitrile butidiene styrene for example, which are initially bonded to the frame, after which a core is foamed in place to completely fill the interior of the panel.
In U.S. Pat. Nos. 3,389,I96 and 3,090,078, methods of making insulated building panels are disclosed wherein outer facing elements are arranged about marginal spacer elements to form hollow interiors which are subsequently filled with a foamable resin composition.
None of the above methods have proven to be completely satisfactory, particularly insofar as multiple manufacturing and assembly steps are required and, in most instances, unless marginal frame members are used, the core composition is exposed at the peripheral edges of the product.
It is the object of this invention to provide a relatively simple and inexpensive process for forming floor tiles, ceiling tiles, trim such as cove base moldings, chair rails, corner guards, truck and boat dock bumpers, sound proofing or other insulating panels and the like.
In the present invention, conventional blow molding or coextrusion techniques are employed in a novel process for forming the articles described above.
In one exemplary embodiment of the invention, a round or square parison is extruded and subsequently blow-molded within appropriately shaped clamp molds to form a one-piece, hollow shell having the desired exterior shape of the finished product. Thereafter, a foamable plastic material is blown into the interior of the shell. The foam material may be blown into the parison while the latter is within the clamp mold, or, alternatively, the parison may be removed from the clamp mold and transferred to a separate foam injection line.
The outside skin, or parison, is preferably formed of a vinyl or other suitable polymeric material, while the foam core is preferably formed of polyurethane, vinyl, or other suitable thermoplastic or thermosetting foam material.
In an alternative embodiment of the invention, the outer polymeric material and inner, foamable plastic material are coextruded through a die formed to provide a composite of the desired cross-sectional configuration. As will be understood by those skilled in the art, the supply of the inner foamed plastic material will be interrupted as required depending on the length of the extruded article, to form the outer end walls of the extruded articles. If the process is a continuous one, the elongated strips may be cut at the solid, interrupted area of the extrusion to form individual articles.
It will be understood that various textures and colors may be incorporated into the formation of the above described articles to provide the desired decorative effect. For example, the pigmentation required to achieve the desired color shade can be added to the plastic composition prior to coextrusion or blow molding. In addition, decorative films can be applied to the walls of the clamp molds so that during the final formation of the parison to the desired shape, the film will permanently adhere to the exterior surface of the parison and be incorporated into the final product. The die surface of a coextrusion die can also be configured to achieve desirable surface effects.
In the production of cove base and other trim moldings in accordance with this invention, it is possible to achieve a real wood look in the sense that the molding can be manufactured with the same thickness and other three dimensional characteristics of real wood molding. For example, wood cove base molding is typically combined with quarter round molding at the lower edge of the cove base to provide a custom finished look. In the present invention, the clamping molds or coextrusion dies may be configured to produce a final cove base product which integrally incorporates the shape of a quarter round molding in the lower part of the cove base. Cove base moldings and other trim items such as chair rails and corner guards can also be produced in accordance with the subject invention in straight sections, or with the exception of the corner guards, in the form of inside or outside corner sections to provide, in effect, perfect corner joints which have a distinctly mitered appearance. The molds or dies may also be configured to incorporate integral male and female connectors into the parison so that various straight and/or corner sections of the cove base molding may be slidably assembled or snap-fit, one to the other, to provide a continuous appearance.
It is a further feature of the invention that attachment rails be provided to facilitate attachment of trim moldings and corner guards to walls or other surfaces. These rails may be of a blow molded or coextruded composite construction similar to the molding itself, or they may be manufactured as solid extrusions, etc. The rails are configured to slidably receive an associated molding, or, preferably, they may be configured to have the molding snap fit over the attachment rail. In a related aspect, the quarter round portion of a cove base molding may be made detachable from the cove base per se, with similar sliding or snap-fit connection structure.
It will also be understood that floor and ceiling tiles may be produced in accordance with the invention which have greater or lesser degrees of resilience, depending on the composition of the foam core interior. The resiliency or cushioning effect which is imparted to floor tile, for example, can provide a degree of safety when used in environments frequented by older persons or infants who are otherwise more likely to suffer falls, etc.
The combination of an outer, integral shell coupled with the resiliency and cushioning effect of the foam is particularly advantageous in the manufacture of modular bumper seals, often used as docking bumpers around truck and boat docks or bays and the like.
Articles formed in accordance with the present invention are characterized by attractive appearance, durability, cleanability, and are relatively inexpensive and simple to manufacture.
Other objects and advantages of this invention will become apparent from reading the detailed description of the invention in conjunction with the accompanying drawings.